Conventionally, such a throttling device is disclosed in, for example, JP 4664095 B (Patent Literature 1).
The above conventional throttling device (expansion valve) is a throttling device in which valve opening degree is varied corresponding to a differential pressure between a refrigerant pressure of a condenser (primary side) and a refrigerant pressure of an evaporator (secondary side) when applied to a refrigeration cycle. This throttling device has a coil spring biasing a valve body in a valve close direction against the differential pressure. Further, the valve-opening degree property is determined corresponding to the differential pressure and a spring constant of the coil spring.